The present invention relates to a device designed for housing and manually controlling an electric relay, such as a thermal relay, associated with a contact or for protection of the latter against overloads.
It is common practice to house in cases, such as cases for electric apparatus, switches protected against overloads and formed by the association of a contact or and a thermal relay.
It will be recalled that the contractor comprises a control electromagnet and defines the ON and OFF operation of a power load, for example a motor, as a function of the current which flows through the coil of the electromagnet. The thermal relay determines the stopping of the motor, particularly in the case of an overload in at least one phase conductor of the motor ; for this, the thermal relay comprises a switch which is controlled by an opening mechanism responsive to the deflection of bimetal strips in the case of overloads and which is electrically connected in series with the coil of the electromagnet of the contractor.
The opening mechanism must be resettable after each tripping operation. Depending on the type of thermal relay considered, resetting is either manual, or automatic, or manual or automatic, by including in the latter case a manual-automatic selection means. Manual resetting is achieved by means of a push-button disposed on the front face of the thermal relay.
In addition, it is often necessary for such a thermal relay to be able to control manually the stopping of the contractor thermal relay assembly by means of another push-button, also disposed on the front face of the thermal relay and acting on the opening mechanism for opening the switch.
When the contractor-thermal relay assembly is fitted in a case, a control push-button is provided on a front wall thereof. By pressing this button an operator acts on the pushers which stop and reset the thermal relay. This stopping and resetting action is transmitted to the pushers of the thermal relay by transmission means whose purpose is to transform the movement of the control push-button into a movement of the controlled pushers, while taking into account lost motion for application on the pushers and misalignment between the push-button and the pushers of the thermal relay.
It is an object of the invention is to facilitate the mechanical transmission between the control buttons of a case housing a contractor-thermal relay assembly of the type described and the pushers actuating the thermal relay.
Another object is to conveniently conciliate both the presence of push-buttons mounted on the front face of the case with a relatively large between axis distance and the use of pushers connected to the thermal relay. and having a relatively small between axis distance.
Yet another object is to allow the user to operate either resetting of the opening mechanism of the thermal relay alone, or stopping--i.e. opening of the switch of the thermal relay--and combined resetting, using simple and compact means.